A preliminary investigation of Eocene larger benthic foraminifera assemblages from Alpine and molasse-type deposits of the Hellenic peninsula (Greece)

Abstract

Larger Benthic Foraminifera (LBF) from five localities in Greece were studied in order to define the morphological features of various nummulitid forms and to describe the foraminiferal assemblages in different geotectonic environments. The selected sites belong to molasse-type formations in Kirki/Thrace Basin and Vasiliki Trikala/Mesohellenic Trough, and carbonate deposits in Alpine Pindos, Ionian and Tripolis geotectonic units.Taxonomic studies combined with biometric data, when possible, enabled us to identify different morphotypes. In the molasse-type deposits of Thrace Basin (Kirki Thrace), N. perforatus was found along with N. maximus and Assilina exponens suggesting correlation with biozone SBZ 16/17, while in the Mesohellenic Trough deposits (Vasiliki Trikala) the association included N. perforatus group, Operculina gomezi group and Silvestriella tetraedra, indicating a Bartonian age, SBZ 17-18A. In outcrops found within Pindos unit (Perivoli Grevena) three different assemblages have been observed in the microbreccious olistholiths, suggesting three distinguished deposits forming quasi-continuous succession spanning from early to middle and up to late Eocene. The Ionian unit (Manoliasa Ioannina) presented a mixed redeposited fauna including late Eocene, early Paleogene and planktonic foraminifera clasts. Finally, the Tripolis unit (Dervenakia and Tripolis) association was interpreted as Bartonian in age, defined by the presence of Operculina gomezi group and N. perforatus group.